One technique for reproducing soil pressure distributions of large structures such as dams and buildings, is to use a scale model which is mounted on the bucket of a centrifuge. The model is subjected to an inertial, or gravity-like force inversely proportional to the scale of the model. It is often desirable to also reproduce dynamic disturbances of the model, such as those which represent earthquakes. The scaling laws require that the acceleration of the model be multiplied by the scale factor, and the displacement to be divided by it. For example, a 1:100 scale model which is to represent a real acceleration of 0.5 g (g is free-fall acceleration at sea level due to gravity) and a peak-to-peak displacement of 5 inches, would be simulated at an acceleration of 50 g and an amplitude of 0.05 inch.
Where a heavy model of a weight such as 1,000 pounds or more is used, and is subjected to a constant acceleration of 100 g in a centrifuge, it is difficult to provide a driving mechanism that can also fit in the centrifuge bucket and which can apply the required large acceleration levels to the model and withstand the large static loading. Furthermore, driver components of a size to produce the large forces for such accelerations, are likely to be more flexible than is desirable for the precise transmission of excitations of small amplitude such as 0.05 inch. A driving mechanism of relatively small size and weight, which could apply large forces over small distances, would be of considerable value in accelerating such scale models as well as in other applications where such activation is required.